1. Technical Field
The present invention relates generally to the up-link and down-link of communications between a wireless network and the Internet, and more particularly to a system and associated method of operation for appending location information regarding a mobile unit to communications sent from the mobile unit operating in a wireless network to a server coupled to the Internet.
2. Related Art
As communications via the Internet have progressed over time, various standards have emerged which attempt to define the manner in which information is transferred over the Internet. These standards define not only the communication mechanisms employed but also the format in which the information is packaged, how information is routed based upon its content and how it is interpreted upon receipt. Examples of communication standards that have been developed specifically for the Internet include the Transfer Control Protocol/Internet Protocol (TCP/IP) and the HyperText Transfer Protocol (HTTP). Further, examples of standards that define communication content, organization and structure include the Hypertext Markup Language (HTML) and the Handheld Device Markup Language (HDML), among other standards.
HTTP provides for the delivery of Uniform Resource Identifiers (URIs) from clients to servers and the delivery of text files from servers to clients and is part of the TCP/IP protocol suite. HTTP is an application-level protocol for distributed, collaborative, hypermedia information systems and has been in use by the World-Wide Web global information initiative since 1990. HTTP allows an open-ended set of methods that indicate the purpose of a request. It builds on the discipline of reference provided by the URI as a Uniform Resource Location (URL) or Uniform Resource Name (URN), for indicating the resource to which a method is to be applied. Messages are passed in a format similar to that used by Internet mail as defined by the Multipurpose Internet Mail Extensions (MIME). HTTP is also used as a generic protocol for communication between user agents and proxies/gateways to other Internet systems, including those supported by the SMTP, NNTP, FTP, Gopher, and WAIS protocols. In this way, HTTP allows basic hypermedia access to resources available from diverse applications.
Content delivered from HTTP servers (also known as Web servers) to Web browsers is delivered in HTML format. HTML describes how a page is to appear in a device-independent manner. Individual devices interpret the HTML and choose how to best display it, given the restrictions of the local environment. The lowest common denominator for HTML was originally specified to be a VT-100 class terminal with an 80-character wide, continuously scrolling display plus a random access pointing device such as a mouse. Today, most Web content requires a more sophisticated browser that can display bit-mapped graphics, run Java programs and execute Shockwave multimedia presentations. HTML does not scale well to small displays and mouseless user interfaces, and is a practical impossibility for delivering information to handheld devices with size, memory and cost constraints.
HDML is a simple language used to define hypertext-like content and applications for mobile units with small displays. HDML is designed to leverage the infrastructure and protocols of the World Wide Web while providing an efficient markup language for wireless and other handheld devices. Congruent with the capabilities and limitations of many handheld devices, HDML's focus goes beyond presentation and layout. HDML provides an explicit navigation model which does not rely upon the visual context required of HTML. As such, HDML offers an efficient means of providing content via the WWW infrastructure to handheld devices such as cellular phones, pagers, and wireless PDA's.
HDTP is an open and freely available protocol specification developed and contributed to the industry by Unwired Planet. HDTP enables any cellular, PCS, or paging network to provide Internet information access from standard handheld devices. HDTP operates with industry standards such as TDMA, CDMA, TCP/IP, UDP/IP, GSM and SMS, and incorporates industry standard encryption algorithms for secure transactions. HDTP is optimized for wireless networks, where the HTTP protocol is not usable due to network latency and throughput. HDTP brings direct Internet information access to wireless networks, regardless of the type of data transport provided. In networks combining multiple protocols, such as SMS, circuit data, or packet data, HDTP allows applications to use the most effective and cost-efficient path to send data to the device's screen.
Devices within a wireless network typically operate according to HDTP/HDML standards. However, devices on the Internet comply the HTTP/HTML standards. Thus, a gateway between the wireless network and the Internet is required to reformat communications passing between the two. As constructed, the gateway supports HDML/HDTP on a side connected to the wireless network and HDML/HTTP on a side connected to the Internet and repackages/reformats communications passing through as appropriate. However, in other applications, the gateway supports HTML/HTTP on a side connected to the wireless network.
In many Internet applications supported by an Internet server, the location of a client is important. For example, a client of a mapping system application provides map information and other services based upon the assumed location of a client. When the client is stationary, the application receives location information a single time by either querying the client or by cross-referencing the IP address of the client to known zipcode locations. Once the location is known, the application proceeds according to the known information.
The mobility of mobile units operating in a wireless network causes problems when the mobile units serve as a client to an Internet based application. In their normal operation, the mobile unit travel over large geographic areas, passing not only from zipcode to zipcode but often from county to county and state to state. In some installations, the mobile unit always accesses the Internet via a single gateway, a gateway IP address ostensibly providing some indication of location of the mobile unit. But, even though the location of the gateway is known, the mobile unit may be a large distance from the gateway visiting in another area. Further, in other installations, the mobile unit accesses the Internet via differing gateways, the selection of which depends upon its operating location.
Thus, there exists a need in the art for a system and method of operation that allows an application operating upon an Internet server to determine a mobile unit's position.